Computer Configuration > Administrative Templates > Google Chrome > Default search provider
Both
HKLM\Software\Policies\Google\Chrome
Setting the policy to Enabled means a default search is performed when a user enters non-URL text in the address bar. To specify the default search provider, set the rest of the default search policies. If you leave those policies empty, the user can choose the default provider. Setting the policy to Disabled means there's no search when the user enters non-URL text in the address bar. The Disabled value is not supported by the Google Admin console. If you set the policy, users can't change it in Google Chrome. If not set, the default search provider is on, and users can set the search provider list. On Microsoft® Windows®, this policy is only available on instances that are joined to a Microsoft® Active Directory® domain, joined to Microsoft® Azure® Active Directory® or enrolled in Chrome Enterprise Core. On macOS, this policy is only available on instances that are managed via MDM, joined to a domain via MCX or enrolled in Chrome Enterprise Core.